1. Field of the Invention
The invention relates to a liquid soap dispenser, more particularly to an automatic liquid soap dispenser which is capable of supplying a predetermined amount of liquid soap when activated and which can prevent leakage of the liquid soap effectively.
2. Description of the Related Art
Liquid soap dispensers are installed in public toilets and deliver small amounts of liquid soap when operated. A first type of conventional liquid soap dispenser requires manual operation of the same before liquid soap can be delivered to the hands of a user. Liquid soap dispensers which belong to this type are inconvenient to use and are unsanitary since physical contact therewith may result in the contraction of germs.
A second type of conventional liquid soap dispenser is capable of delivering automatically small amounts of liquid soap onto the hands of a user without manual operation thereof or physical contact therewith. Liquid soap dispensers which belong to this type usually employ an infrared unit to control the dispensing of liquid soap automatically. Upon detection of a target, such as the user's hands, the infrared unit activates a pump actuating unit to activate correspondingly a spring-type pump unit in order to dispense a predetermined amount of liquid soap from a soap container. This type of liquid soap dispenser is convenient to use and prevents the dispensing of excessive amounts of liquid soap.
Prolonged use of liquid soap dispensers which belong to the second type, however, results in several drawbacks. For example, fatigue of the spring-type pump unit occurs, thereby affecting the ability of the pump unit to return to a fully-closed position and thereby diminishing the amount of liquid soap dispensed by the dispenser. Furthermore, leakage of the liquid soap can occur since the pump unit is unable to return to the fully-closed position.